Braces for immobilizing joints in the human body are known. With particular reference to the lower extremity, devices are known which range from a full double upright conventional metal brace for permanent use in a neuromuscularly disabled individual to a knee immobilizer which incorporates metal stays with a soft foam and cloth outer body for nonrigid immobilization of knees after injuries and minor surgeries.
The present cloth and metal knee immobilizer is inadequate for other purposes and often fails to provide good immobilization of the knee joint. For example, an individual will initially have approximately 15.degree. to 20.degree. of knee flexion due to fluid on the knee joint after injury or surgery. Therefore, it is very painful to attempt to straighten the knee acutely to fit an immobilizer.
A number of braces have been developed to control knee stability which incorporate a knee hinge. One cast brace is made from a variety of casting materials in which various types of hinges have been designed, some of which limit the motion within a specific arc. At the present time, some orthopedists repairing the medial collateral ligament position a postoperative splint or full long leg cast to hold the knee between 30.degree. and 60.degree. of flexion. This position is maintained for three to four weeks. A plaster type cast brace is then applied which has hinges incorporated therein to allow motion between a 30.degree. to 60.degree. arc from full extension. This brace is worn for another four week period at which time this brace is removed and a knee immobilizer is applied to stabilize the joint. There is a tremendous cost involved with multiple cast changes. In addition, a knee immobilizer is ultimately required at the end of the cast immobilization period.
An additional problem encountered with known knee immobilizers relates to properly positioning the immobilizer on a patient. The common immobilizer having medial and lateral stays sewn permanently to the device should ideally be placed along the mid-lateral line medially and laterally on the leg. However, this occurs only if the circumference of the leg is appropriate for the size immobilizer. Without appropriate fit, the medial and lateral stays become anterior to the knee joint axis if the device is too large. If the device is too small, the medial and lateral stays will be too far posterior to the knee. One immobilizer currently sold has movable medial and lateral stays, which somewhat improves the ability to properly position the immobilizer.
Another major problem with the known knee immobilizers are their inability to be positioned on a patient with a conical shaped thigh. This shape is the most common in individuals and therefore great difficulty arises in maintaining the immobilizer in the proper position. Finally, a knee immobilizer often does not provide rigid immobilization. A poor fit on a patient may permit flexure of the knee within a 30.degree. arc.